Cardiovascular risk factors were studied in a random sample from the urban and rural population of the Cap-Bon, including 692 men and women, aged 35-50 years. In this sample, including 56 % urban dwellers, the mean total cholesterol was higher in urban areas (4.64 mmol/l) than in rural areas (4.16 mmol/l). In urban areas 10.2 % of the subjects had values above 6.2 mmol/l compared with 6.6 % in rural areas. Obesity was much more frequent among women (35.2 % versus 26.3 %) but less frequent among men (16.0 % versus 5.4 %) in urban and rural areas. Diabetes was found in 8.8 % of men and 10.4 % of women in urban areas, and only 0.8 % and 3.9 % in rural areas. Hypertension was found in 13.8 % of women and 11.6 % of men in urban areas, 13.3 % and 4.0 % in rural areas (13.3 %). Cigarette smoking was found in 60.7 % of men in urban areas and 75.8 % in rural areas (p < 0.05).